Pros: Wide open sound stage, full rich textured sound. Comfortable to wear due to large, cushioned earpad. Doesn't feel hot after hours of listening.
Cons: Home use only (wireless with large base), charging time. Initial retail was too high (600-700 bucks), a bit goofy looking given their size.
One of the real high points of the RS220's is the wide open sound stage. Music sounds full, rich, and textured. Live performances in particular have an "in person" feel more than any other phones that I've owned. I'm a little surprised they're not more common among "head-fi'ers". Especially after seeing Jude M's initial review on their you tube channel.
One limiting factor that might give priority to other phones at the original retail price point is the lack of portability. They can only be used at home or office. Anyone looking for a more versatile headphone that can be used at home/office AND while on the move should look elsewhere. Perhaps, many that tried these at first ended up buying something like the Sennheiser HD650's for the added flexibility.
If you're looking for a pair of phones exclusively for home or office, the RS220's won't be a disappointment. My recent setup MacBook Air Pro or IPad Air 2 streaming Tidal HIFI to Dragonfly Red connected to the RS220 base via RCA analog cable.